Poly(neutral red) / Multi-walled Carbon Nanotube Composite Modified Electrochemical Sensor for Ratiometric Detection of Estriol

A poly( neutral red) / multi-walled carbon nanotube nanocomposite modified electrochemical sensor was established for ratiometric sensing of estriol. The poly( neutral red) was used as the internal reference electroactive probe, and the oxidation peak current ratio of estriol to poly( neutral red) was used for accurate quantitative detection of estriol. The poly ( neutral red ) / multi-walled carbon nanotube nanocomposite was demonstrated good electroconductivity and high electrocatalytic performance which could improve the detection sensitivity. The response of the ratiometric sensor was linearly proportion to the estriol concentration in the 0. 1-2. 0 mu mol/ L range, with a limit of detection (S/N=3) of 0. 08 mu mol/ L. The electrochemical oxidation reaction of estriol on the poly (neutral red ) / multiwalled carbon nanotube nanocomposite / glassy carbon electrode was demonstrated to undergo a two-electron/two-proton process. Moreover, the sensor had high sensitivity, strong anti-interference ability and good stability, and was successfully applied to testriol analysis in pharmaceutical cream, urine and lake water samples.